The present invention relates to a communication terminal having an energy saving function and capable of managing time even in an energy saving mode. More particularly, the present invention relates to a facsimile apparatus with an energy saving function and capable of performing, e.g., time appointed transmission even in an energy saving mode.
Various kinds of apparatuses available today have an energy saving feature for reducing power consumption. Particularly, a facsimile apparatus belonging to a family of communication terminals is required to save power while in a stand-by state, and is provided with an energy saving function. Japanese Patent Laid-Open Publication No. 57-168573, for example, discloses a facsimile apparatus including a main controller and a subcontroller implemented by CPUs (Central Processing Units). The main controller is supplied with power from a main power source during transmission and receipt. The subcontroller is supplied with power from an auxiliary power source while the apparatus is in a stand-by state. In the stand-by state, only the auxiliary power source is held operative in order to save power.
Japanese Patent Laid-Open Publication No. 1-119813 teaches a facsimile apparatus in which a main power source is turned on when a call signal coming in through a communication circuit is detected, thereby reducing power consumption. Further, Japanese Patent Laid-Open Publication No. 3-105408 proposes an electronic apparatus so constructed as to interrupt a clock while preselected control processing is not required.
It is a common practice with the conventional facsimile apparatus having an energy saving function to assign a time managing function to the main controller. Specifically, the main controller controls the operation of various functions needing time management, e.g., time appointed polling receipt, time appointed transmission, power saving timer, and night timer. However, the auxiliary controller also included in the apparatus lacks the function of managing time. This, coupled with the fact that the main power source for feeding power to preselected units including the main controller is turned off in an energy saving mode, makes it impossible to manage time in the energy saving mode. Therefore, the conventional apparatus cannot, in the energy saving mode, control the operation of the various functions mentioned above.
With any one of the conventional facsimile apparatuses, it is possible to cancel the energy saving mode in response to the operator's manipulation or a ringing signal or similar signal representative of receipt. However, because the apparatus lacks the function of managing time, it cannot execute control for cancelling the energy saving mode at a preselected time.